Material Removal Mechanism and Surface Quality Evaluation of Graphite Ultrasonic Vibration Milling
Surface fragmentation often occurs during the milling process of graphite mold.Ultrasonic vibration assisted machining can improve surface fragmentation and machining quality.However,currently,there is a lack of the research on the material removal mechanism and machining quality evaluation of ultrasonic vibration assisted milling of graphite materials have not been studied.Through ultrasonic vibration assisted milling experiments,the removal mechanism of graphite materials during ultrasonic vibration assisted milling and the influencing factors on the quality of machined surfaces are investigated.The effects of ultrasonic vibration assistance on cutting force,acoustic emission signal strength,chip and surface morphology characteristics are analyzed.And the influence of processing parameters on surface roughness is explored.The results indicate that the material removal mechanisms during graphite material milling can be divided into micro crushing removal and large scale crushing removal.Ultrasonic vibration assistance can improve the proportion of micro crushing removal mechanism,improve machining quality,and reduce cutting force by about 25％and acoustic emission signal strength.Through process parameter experiments,it is found that under ultrasonic vibration assisted milling conditions,reducing the radial cutting depth and feed rate per tooth can reduce surface roughness by more than twice.Choosing an appropriate ultrasonic amplitude can help suppress surface fragmentation and improve the quality of the processed surface,but increasing the cutting speed can weaken the effect of ultrasonic vibration,and excessive ultrasonic amplitude can also lead to poor surface quality.In summary,ultrasonic vibration assistance has a significant effect on suppressing surface fragmentation in graphite milling,providing guidance for further solving the problem of surface fragmentation in graphite machining.
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